Balancing mechanism and method for continuous casting molds

ABSTRACT

A mechanism and method for balancing the forces applied to a continuous-casting mold as it oscillates and thereby minimizing vibration in the supporting structure. The mold is oscillated by cams which engage cam followers on the mold frame. Auxiliary cams engage cam followers on a balancing mass to move the latter always in the opposite direction from the mold. The balancing mass is approximately equal to the mass of the mold and parts which oscillate therewith.

United States Patent Teplitz [451 Nov. 28, 1972 [5 BALANCING NIECHANISMAND 2,815,551 12/ 1957 Hessenberg ..164/83 METHOD FOR CONTINUOUS CASTING3,258,815 7/1966 Reinfeld ..164/83 X MOLDS 3,386,494 6/1968 Yearley..164/83 X Alfred Teplitz, Pittsburgh, Pa.

Assignee: United States Steel Corporation Filed: Nov. 12, 1970 Appl.N0.: 88,781

Inventor:

US. Cl ..164/260, 164/83 Int. Cl. ..B22d 27/08 Field of Search ..l64/4,83, 287, 288, 71, 260,

References Cited UNITED STATES PATENTS Examiner--J. Spencer OverholserAssistant Examiner-John S. Brown Attorney-Walter P. Wood [57] ABSTRACT Amechanism and method for balancing the forces applied to acontinuous-casting mold as it oscillates and thereby minimizingvibration in the supporting structure. The mold is oscillated by camswhich engage cam followers on the mold frame. Auxiliary cams engage camfollowers on a balancing mass to move the latter always in the oppositedirection from the mold. The balancing mass is approximately equal tothe mass of the mold and parts which oscillate therewith.

6 Claims, 1 Drawing Figure PATENTEDNHV 28 I972 IIVVEIVTOR FRED TEPL/ IBY Mm 14/144 Affane) BALANCING MECHANISM AND METHOD FOR CONTINUOUSCASTING MOLDS This invention relates to a balancing mechanism for anoscillating continuous-casting mold and to a method of balancing forcesapplied thereto.

In a conventional continuous-casting operation, liquid metal is pouredcontinuously into a water-cooled mold open at the top and bottom. Apartially solidified casting emerges from the bottom, after which itsolidifies throughout and is further processed as known in the art. Themold is oscillated vertically to prevent the casting from sticking. Oneform of drive for oscillating the mold includes a pair of drivencamshafts journaled to the supporting structure at opposite sides of themold. Cams on these shafts engage cam followers on the mold frame.Reference can be made to Bode U.S. Pat. No. 3,381,743 for an exemplaryshowing of an oscillating mold which has a drive of this type. Onedifficulty has been that the oscillations induce objectionablevibrations in the supporting structure.

An object of the present invention is to provide a balancing mechanismand method which minimize vibration in the supporting structure of acam-driven oscillating mold.

A more specific object is to provide a balancing mechanism for anoscillating mold, which mechanism includes auxiliary cams on thecamshaft and cooperating force-equalizing means, whereby the upward anddownward forces on the camshaft are balanced throughout the oscillatingcycle.

In the drawing: I

The single FIGURE is a diagrammatic isometric view of a portion of acontinuous-casting installation equipped with my balancing mechanism.

The installation shown in the drawing includes a multifloor supportingstructure, two floors at different levels of which are shown at and 12.An oscillating mold frame 13 is situated above floor 10 at the higherlevel and carries an open-ended water-cooled mold l4. Horizontalcamshafts 15 and 16 are journaled in bearings 17 on floor l0 and aredriven from a common drive 18 through bevel gears 19. Camshaft 15 islocated respective auxiliary cams 25. Pipes 27 connect the cylinderswith a source of compressed air (not shown) through a pressure regulator28. The cylinders have reciprocable piston and piston rods 29 whichcarry counterweights 30. Cam followers 31 are journaled to the upperfaces of the counterweights at locations to cooperate with the auxiliarycams 25. My balancing mechanism also includes similar parts associatedwith the other camshaft 16, but I have not repeated the description. I

In operation, mold 14 is oscillated vertically in the usual way whilemetal is introduced thereto to produce a casting. The mold frame 13 andmold 14 move upwardly as the segments of earns 20 and 21 of increasingradii engage the cam rollowers 22. At the same time the segments of theauxiliary earns 25 of increasing radii engage the cam followers 31 andforce the. piston rods under the near side of frame 13 and carries apair of drive earns 20 near the opposite ends of the frame. Camshaft 16is located under the far side of frame 13 and carries a pair of drivecams 21. The two Camshafts and their drive cams are alike but ofopposite hand, and they rotate in opposite directions. Frame 13 has camfollowers 22 journaled to its underside at locations to cooperate withcams 20 and 21. As the Camshafts l5 and 16 rotate, the earns 20 and 21act on the cam followers 22 to oscillate the frame 13 and mold 14vertically. The structure thus far described and its operation areknown, as shown for example in the aforementioned Bode patent.

The balancing mechanism of my invention includes a pair of auxiliarycams 25 mounted on camshaft 15 adjacent the respective drive cams 20.The auxiliary cams and drive cams are of similar configuration butdisplaced 180 from each other; that is, the sectors of the auxiliarycams of maximum and minimum radii are aligned horizontally with thesectors of the drive cams of minimum and maximum radii respectively. Thelower floor 12 of the supporting structure carries a pair of upstandingpneumatic cylinders 26 beneath the 29 and counterweights 30 downwardly.The parts move in the opposite directions as the segments of the cams ofdecreasing radii engage the cam followers. Pressure in cylinders 26urges the cam followers 31 into engagement with the auxiliary cams 25throughout the cycle. I maintain a constant pressure in these cylindersby suitably adjusting the pressure regulator 28.

According to my balancing method, I maintain a relation such that:

M1 a M2 (12 0 where:

M =Total mass of frame 13, mold l4, cam followers 22 and all other partsattached thereto.

M Total mass of counterweights 30, cam followers 31, piston and pistonrods 29, corresponding parts as-' sociated with camshaft l6, and otherparts attached thereto.

a momentary acceleration of M a momentary acceleration of M M and M areequal; hence a =a The mass of each counterweight assembly equals M Theupward force exerted by each of the four cylinders equals twice M sothat the forces between the drive cams and their followers are the sameas the forces between the auxiliary cams and their followers. 7

The foregoing relations of mass and pressure are ideal and effectivelyeliminate vibration in the supporting structure. Nevertheless it isapparent that I can minimize vibrations with reasonable effectivenessusing masses and pressures which only approximate this ideal relation.Also I can substitute coil springs for air cylinders to apply upwardforces to the counterweights if the mold operates within a narrow speedrange.

I claim:

1. In a continuous-casting installation which includes a supportingstructure, a mold supported for vertical movement on said structure,camshafts journaled to said supporting structure, drive cams carried bysaid Camshafts, and cooperating cam followers associated with said mold,said Camshafts, cams and cam followers constituting a drive forvertically oscillating'said mold, the combination therewith of abalancing mechanism operatively connected with said drive to minimizevibrations in said supporting structure broughtabout by the oscillatingmovement of said mold, said balancing mechanism comprising auxiliarycams carried bysaid camshafts, and means carried by said supportingstructure and cooperating with said auxiliary cams to receive forcesopposing the forces applied to said mold.

therewith is approximately equal to the mass of said rods,counterweights and parts which move vertically therewith.

5. A combination as defined in claim 4 in which the means urging saidrods upwardly includes pneumatic cylinders and means for supplyingcompressed air to said cylinders under regulated pressure, the forceexerted by said cylinders being approximately twice the second-namedmass.

6. In a continuous-casting operation in which liquid metal is pouredcontinuously into a water-cooled mold open at the top and bottom, apartially solidified casting emerges from the bottom, and the mold iscamoscillated vertically, the improvement which comprises balancing theupward and downward forces applied'to said mold in oscillating it, thebalancing forces being cam-applied in the opposite direction to theoscillating forces against a mass approximately equal to the mass of themold and the parts which oscillate therewith, the mass against which thebalancing forces are applied being held against the cams with a forceapproximately twice its mass.

1. In a continuous-casting installation which includes a supportingstructure, a mold supported for vertical movement on said structure,camshafts journaled to said supporting structure, drive cams carried bysaid camshafts, and cooperating cam followers associated with said mold,said camshafts, cams and cam followers constituting a drive forvertically oscillating said mold, the combination therewith of abalancing mechanism operatively connected with said drive to minimizevibrations in said supporting structure brought about by the oscillatingmovement of said mold, said balancing mechanism comprising auxiliarycams carried by said camshafts, and means carried by said supportingstructure and cooperating with said auxiliary cams to receive forcesopposing the forces applied to said mold.
 2. A combination as defined inclaim 1 in which the means cooperating with said auxiliary cams includesupstanding vertically moving rods, counterweights carried by said rods,cam followers carried by said rods and engaging said auxiliary cams, andmeans urging said rods upwardly.
 3. A combination as defined in claim 2in which the means urging said rods upwardly includes pneumaticcylinders and means for supplying compressed air to said cylinders underregulated pressure.
 4. A combination as defined in claim 2 in which themass of said mold and the parts which oscillate therewith isapproximately equal to the mass of said rods, counterweights and partswhich move vertically therewith.
 5. A combination as defined in claim 4in which the means urging said rods upwardly includes pneumaticcylinders and means for supplying compressed air to said cylinders underregulated pressure, the force exerted by said cylinders beingapproximately twice the second-named mass.
 6. In a continuous-castingoperation in which liquid metal is poured continuously into awater-cooled mold open at the top and bottom, a partially solidifiedcasting emerges from the bottom, and the mold is cam-oscillatedvertically, the improvement which comprises balancing the upward anddownward forces applied to said mold in oscillating it, the balancingforces being cam-applied in the opposite direction to the oscillatingforces against a mass approximately equal to the mass of the mold andthe parts which oscillate therewith, the mass against which thebalancing forces are applied being held against the cams with a forceapproximately twice its mass.